Access the Discovery Channel's Krakatoa website that includes VolcanoExplorer. On the left, you'll see a menu of choices. Click on "Build your own volcano and watch it erupt," right beneath "Virtual Volcano."
Use the mouse to choose the viscosity of your volcano's magma and the amount of gas present. To learn more about these two components, click on the two links at the bottom of the page, labeled "Viscosity Info" and "Gas Info." Viscous magma is thicker and has more silica, leading to lava that flows more slowly. The more gas that is present, the more powerful the eruption.
Click the "Set Conditions" button once you've chosen magma viscosity and gas content. The page will change to show you the type of volcano that is associated with your settings. For example, a cinder cone volcano is associated with high gas levels and a medium level of viscosity. If you want to try different settings, click on "Change Settings" at the bottom to go back. If you're ready to move on, click "Start Eruption."
Watch the simulated eruption on the screen. The website will then give you a detailed description of the eruption at the bottom. For example, the cinder cone volcano yields a strombolian eruption, a loud spectacle that has little danger for the surrounding area. Cinder will shoot out of the volcano in sizes from marbles to boulders, but there is minimal lava flow. Replay the eruption if desired.